Another manual workaround is to convert as root using ImageMagick all the PNG causing error in the folder /usr/share/mplayer/skins.
Items have to be converted in the format PNG24 and renamed PNG after cancel the existing PNG.
You have to do only with items causing error, not all.
It's a bit annoying but it works for me and you have the mplayer-gui working.
I'm on xubuntu 14.04.
mplayer version 2:1.1+dfsg1-0ubuntu3
mplayer-gui version 2:1.1+dfsg1-0ubuntu3
Another manual workaround is to convert as root using ImageMagick all the PNG causing error in the folder /usr/share/ mplayer/ skins.
Items have to be converted in the format PNG24 and renamed PNG after cancel the existing PNG.
You have to do only with items causing error, not all.
It's a bit annoying but it works for me and you have the mplayer-gui working.
I'm on xubuntu 14.04.
mplayer version 2:1.1+dfsg1- 0ubuntu3 0ubuntu3
mplayer-gui version 2:1.1+dfsg1-